Electrosurgery is the application of electrical current to tissue for the purpose of surgically altering the tissue. It is a method commonly used for a variety of medical procedures including, but not limited to, resecting or vaporizing tissue (typically by ablation) associated with warts, benign tumors, and tissue growth such as that associated with Benign Prostatic Hyperplasia (BPH). During such procedures, electrosurgery can also be used for controlling bleeding through coagulation. Electrosurgical devices generally operate by providing electrical current traveling from an active electrode through target tissue to a return electrode. Depending on the characteristics of the energy (voltage, frequency, wattage, for example) being passed through the tissue, and the device electrodes (size, shape, distance, for example), the tissue can be transected, vaporized or coagulated.
Traditionally there have been two primary types of electrosurgical equipment: bipolar and monopolar. Bipolar electrosurgery provides the active and return electrode on the surgical device itself in close proximity to the targeted site, while monopolar electrosurgery provides only the active electrode at the targeted site, and the return electrode is generally a conductive plate that is secured to the patient's outer skin surface. In monopolar electrosurgery higher voltages are required to overcome the associated resistance of the patient's body, which serves as a necessary part of the circuit. In bipolar electrosurgery, less input power is needed, but the effect on the targeted tissue is limited by a number of factors, including the proximity of the active to the return electrode, the size and shape of the electrodes, the shape and regularity of the electric field that is created, and the ratio of the surface area of the return electrode to the surface area of the active electrode.
Although present electrosurgery equipment and techniques are suitable for many applications, a need remains for equipment and techniques that offer improved ablation and coagulation and greater control over the ablation and coagulation processes.